pcray1231 wrote:It is pretty much proof that in Dimock, the contamination is likely from drilling activity, which I think we all knew anyway.

Don't forget that only recently the industry was denying that their drilling caused the problems at Dimock.

Now it's "we already knew that."

The Duke study isn't likely to be perfect, or the last word because there will probably be a lot more studies in the near future. But I wouldn't be so quick to say that it is just a "political" document, as some have said.

Duke is a major reseearch university, the paper is peer reviewed, and it was published by the National Academy of Sciences. It's not just someone typing on a blog.

Don't forget that only recently the industry was denying that their drilling caused the problems at Dimock.

True, but I think every 3rd party observer knew the truth on that one. Maybe not the method, but that it was related to drilling. Other than the industry reps, noone really defended them on it. I think even the courts, weren't they forced to pay damages there?

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The Duke study isn't likely to be perfect, or the last word because there will probably be a lot more studies in the near future. But I wouldn't be so quick to say that it is just a "political" document, as some have said.

Agreed, and even the researchers said as much. Thats why I hate MSM articles about science. Issues like this, every study gives you a snippet of info, but only after 50 or 100 such studies does the picture start to get a little clearer. These studies are not final conclusions, rather, they're a method of conversation among scientists. You can't say a single study is garbage, its just a very small part of the whole discussion. But the media and political sides tend to take a single study and run with it as the gospel, when thats never what the scientists intended.

Likewise, as a scientist myself, I'm not going to sit here and say that there was intentional bias or anything here. It is what it is, these guys set out to test for contamination near gas wells. They started too late to get "before" measurements, they probably didn't get permission to test in as many places as they'd like. They ended up getting valid measurements on 4 or 5 wells. And they found that 1 of them was indeed contaminated. Not only that, but they essentially proved that the contamination was due to drilling activity. Not bad for one paper.

1 in 4 or 5 isn't enough to make a statistical conclusion when there are 1000's of wells out there. From the data, an overall rate of 1 in 2 or 1 in 10,000 are still possible. But getting actual valid statistical conclusions in a situation like this is a job way too big for 1 study. Another group will copy the study on 4 or 5 more wells, then another on 4 or 5 more, and eventually you collectively have a decent amount of data where maybe you can make some statistical conclusions.

pcray1231 wrote:Gone4Day, thanks, good info as always. I do have a question. I am aware that the gas can be chemically traced to a formation, likely even to an area within a formation. But I'm not sure how specific they can get. For instance, if 2 wells are 3 miles apart and tapping the same shale formation, could you chemically determine which exact well the gas came from?

Just trying to inform the discussion. Short answer is no. The longer answer...

There are two types of gas found in nature - biogenic, formed from the decay of organic matter and thermogenic, formed from the thermal cracking of organic matter. The former is almost all methane while the latter contains longer chain hydrocarbons that can only be formed through thermal cracking. These two are easy to distinguish from their gas chromatograms. Shallow gas can be one or the other or a mixture of the two.

With themogenic gas, it is often possible to correlate them to their source rocks or each other using biomarkers and/or isotopic composition. However, the Devonian shales all have very similar organic matter and there is substantial mixing making it nearly impossible to correlate them with a specific shale layer. So basically all the thermogenic gas looks about the same and it would therefore be unlikely that you could distinguish gas of one well from another nearby. The best you can do is constrain it by depth based on maturity.

Looking at the study, its actually from the Nicholas School of the Environment. The Duke guy is the last author mentioned, which usually means he had the least to do with it. He probably runs the geochemistry lab at Duke. Generally these studies are attributed to the lead author, not the last contributor. So that's a little bit misleading.

Since they had to resort to comparing isotope ratios, it suggests that most if not all their samples are of mixed origin. All they are really showing is more thermogenic gas near gas wells. Its a chicken or egg argument. Do they drill because of higher gas content or is higher gas content because they drilled? Without before and after data, there's no way to tell.

The simple way to test a well for leakage is by pressure testing. If it can't maintain pressure, its leaking.

Not invalid. Just a small amount of info. What's invalid are the media conclusions, not the researchers'. The research conclusions are merely incomplete, which is going to happen nearly 100% of the time if you rely on a single study. I'll explain the best I can. The writers aren't real forthcoming with the data, you have to back it out, which I'm doing to the best of my ability. I'd prefer if they had a table with each test site, location, and results. But they only give you that in graphical form, without exact location, and for overall conclusions they rely on averages.

Active site = near gas well. Non active site = far from gas wells.

Genesee formation - located in NY. They tested 1 "active site", and 8 non active sites. There was no increase in methane at the active site, the non active sites actually contained more methane. But the active site is only 1 data point, which is hard to make conclusions from.

Loyalsock formation - located in Bradford County. They tested 7 active sites and zero non active sites. The active sites averaged fairly high in methane, but because they tested no nonactive sites, you can't take this as "enriched". There is no baseline comparison.

Catskill formation - all of the "conclusions" are drawn from here, the test sites are in Susquehanna, Lackawanna, and Wayne counties. Per Table I, they have 13 baseline "active" test sites, and 5 non-active that they used for data. The map in Figure 1 shows more data points than that, so I assume that means they have thrown out some invalid data from a few of the sites, which is normal (assuming the data was truly invalid). But also keep in mind, thats 13 test sites near active wells, not 13 different active wells.

From the map on Figure 1, it appears that 8 of the 13 "active" sites in the Catskill formation are from right around the Dimock well, and 5 are from other wells. For the Table I results, what they have done is averaged these results in with the other (unenriched) active well sites, and yes, shown enrichment of methane in "active" sites. But surprise surprise, if you look at Figure 4A, of the "active" Catskill data, there are exactly 8 tests that were enriched with methane, and 5 that fall along the baseline with methane concentrations around the same levels as the non-active sites.

Thus, it is not clear, but it is possible, even likely, that the ONLY sites that were enriched with methane due to drilling activity in this study were located very close to Dimock. By averaging those results in with other "active" sites in the Catskill, as well as active sites in the Loyalsock (high methane but no baseline comparison) and Genesee (active well not enriched), the average is indeed higher for active sites than non-active sites, but this all may or may not be attributed solely to a single gas well in Dimock.

From the article, "In the Bradford County problems that contributed to the million-dollar fines, the department said that improper well casing and cementing allowed natural gas to seep into groundwater and contaminate 16 families' drinking water wells. The department began investigating the complaints last year. In November, it won approval of stronger well-casing and cementing rules that a top DEP official has said would have prevented the gas migration."

Tends to agree with what Pcray has been saying about well casings. Contacts I have in the energy industry tell me that with the proper tests, processes, and materials casing failures should be extremely low percentage.

Also, one of the frequent requests here and throughout the environmental community is slow things down. If this is done the proper tests can be done, the proper processes followed and proper materials for casing can be developed. Instead we have a wild west scenario where some companies act responsibly, with the proper safety nets and proper procedures and other companies wing it. Meanwhile it takes mistakes like the ones Chesapeake had for DEP to bring about changes necessary to force companies to act responsible.

But it says the previous study did find methane, this study did not find brine. These are two different things, unless I'm missing something...

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"This research demonstrates that freshwater aquifers in northeastern Pennsylvania have not been impacted by natural gas development activities," said Kathryn Klaber, president of the Marcellus Shale Coalition.

Poor wording Kathryn Klaber. The research demonstrates that drinking water has not been impacted by brine. Freshwater aquifers are without a doubt being impacted now, and will continue to be in the future, by natural gas development activities. Whether it be from dewatering or increased siltation due to all the new/improved dirt roads. And you can damn well be sure that fracking waste water will find it's way back into the water cycle at some point. That's the way nature works.

Considering the depth of the shale formations it is should be possible to get at the gas without contaminating the aquifer. They hit an underground freshwater river at about 8k feet and a brine sea at 13k before hitting gas. Though that depends on those doing the drilling. They drilled two wells on my Grandfathers 50 acres and only one produces because they did not case the well deep enough, ground water got in and made "green gel" that clogged the well. Our well water in the area was never great because of 19th century coal mining but there has been dissolved gasses in the water since then, I'm not in the area now but it would be interesting to see if the tap-water will light up. The only thing you can't argue is the insane water consumption, they were forced to re-pave the road after drilling because the truck traffic from the wells to 12 Mile Run destroyed the road.